Assembly decoding help?
catamorphism at gmail.com
Tue Mar 4 22:21:37 EST 2008
On 3/4/08, Justin Bailey <jgbailey at gmail.com> wrote:
> I'm trying to get a feel for the assembly output by GHC on my
> platform. Below is a module containing one function and the associated
> assembly. I've put in comments what I think is going on, but I'd
> appreciate it if anyone could give me some pointers. I'd really like
> to know three things:
> * Why does _Add_unsafeShiftR_info check if (%esi) is 3?
> * What's going on in _s86_info?
> * At the end of _s87_info, 8 is added to %ebp and then jumped to. Is
> that a jump to the I# constructor and, if so, how did it's address get
> to that offset from %ebp?
I agree with Stefan's advice: read the STG code, especially to answer
the second two questions (-ddump-stg), and read the STG paper (if you
Implementing lazy functional languages on stock hardware: the
Spineless Tagless G-machine, SL Peyton Jones, Journal of Functional
Programming 2(2), Apr 1992, pp127-202.
Then if anything's still not clear, ask on the mailing list.
Tim Chevalier * http://cs.pdx.edu/~tjc * Often in error, never in doubt
"The future is not google-able." -- William Gibson
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